JP7396871B2 - Inert gas generator for aircraft fuel tank inerting system and inerting method - Google Patents

Description

The present invention relates to the technology of inert gas generation systems, particularly for use in inerting systems for at least one fuel tank of an aircraft, such as an airplane, helicopter, etc.

In the field of aeronautics, inert gases, such as nitrogen, or any other inert gas such as carbon dioxide, are used in these fuel tanks for safety reasons to reduce the risk of fuel tank explosion. It is well known to use inerting systems for injecting the above-mentioned inert gases.

Generally speaking, an inert gas generator includes a system with an air inlet and means for distributing airflow to a plurality of air separation modules, the plurality of air separation modules being arranged on the air system. are placed in parallel to deplete the oxygen in the air and produce nitrogen-enriched inert gas at the outlet.

Current inerting systems allow inert gases to be introduced into the fuel tank whose level of flammability is incompatible with the approved regulations in the field of aviation, which are well known to those skilled in the art. .

In practice, the inerting system is sized to introduce an amount of inert gas calculated according to the aircraft's specific operating point, particularly at 4,000 feet during the descent phase.

With this specific operating point, it is possible to calculate the requirements for inert gas flow rate and purity and deduce from this the number and type of air separation modules required. Apart from this point for sizing the aircraft, less inert gas is required in the fuel tank.

From the above, for some flight phases the inert gas generators implemented in the current prior art will be too large compared to the actual requirements for inert gas. The same applies to filter elements and other components of the deactivation system, which increases the weight, consumption and cost of the deactivation system during these flight phases.

One of the objects of the present invention is therefore to provide an inert gas generator, as well as an inerting method, which optimizes the size and use of the inerting system, in order to reduce the consumption and cost of use. It is about overcoming the shortcomings of technology.

It is also another object of the present invention to provide such an inert gas generator that includes longer-life components.

For this purpose, a generator has been developed which generates an inert gas from an air stream introduced into an inerting system, in particular for at least one aircraft fuel tank, which generator has an air inlet and a plurality of air inlets. means for distributing airflow to the separation modules; and a plurality of air separation modules arranged in parallel on the air system to deplete oxygen in the air and to deplete nitrogen-enriched waste at the outlet. Generates active gas.

According to the invention, the inert gas generator is programmed with a distribution means for selectively supplying air to a single, some or all air separation modules depending on the flight phase of the aircraft. control unit.

The use of air separation modules is thus linked to the actual requirements for inert gases, which are determined in particular by the flight phase of the aircraft. Thus, the inert gas generator consumes the amount of air required to meet the requirements for inert gas. All overconsumption is avoided. The invention thus makes it possible to reduce the operating costs of the system and the inert gas generator, while also reducing wear and thus extending the life of the components in the inert gas generator.

For example, the control unit is programmed to supply air to a single air separation module when the aircraft is in the cruise phase and to a single or some modules when the aircraft is in the climb phase.

Similarly, the control unit is preferably programmed to supply air to several or all of the air separation modules when the aircraft is in the descent phase.

Based on this concept, several embodiments have been designed, either alone or in combination.

For example, according to one particular embodiment, when a single or some air separation modules are supplied with air, the control unit selects the air separation module of the plurality of air separation modules that has the least accumulated operating time. Programmed to supply air.

According to another embodiment, when the single or some air separation modules are supplied with air, the control unit controls the best performing of the plurality of air separation modules, i.e. the generated inert gas is programmed to supply air to the air separation module that has the lowest level of oxygen in the air.

Air separation module performance can be measured while the aircraft is in the descent phase, on the ground, or in the cruise phase.

Advantageously, the inert gas generator includes at least one oxygen analyzer and an oxygen analyzer for measuring the inert gas at the outlet of each air separation module, in order to measure the performance of each air separation module independently of each other. and means for directing.

This feature makes it possible to check the purity of the inert gas at the outlet of each air separation module and, if this purity is based on performance criteria, select which of the air separation modules should be used. . This feature also makes it possible to check the performance of the air separation modules one by one, e.g. when the aircraft is in the cruise phase, on the ground or in the descent phase, and it is possible to check the performance of the air separation modules one by one, e.g. Provisions can be made to replace air separation modules. In the prior art, it is currently not possible to test the performance of each air separation module independently, so when a loss in performance is detected, air separation The entire module assembly must be replaced frequently.

In another embodiment, used alone or in combination with those described, when a single or some air separation modules are supplied with air, the control unit controls one of the plurality of air separation modules. The air separation module is programmed to alternate supply of air at specified time intervals.

In this configuration, the invention provides for switching between different air separation modules after a specified period of use, for example by switching to the next module, the best performing module, or the module with the least accumulated operating time. can equalize the wear of the various air separation modules.

In this way, the use and wear of the various air separation modules can be equalized.

According to one particular embodiment, the airflow distribution means are in the form of a suitable valve, for example multi-channel, which valve can then direct the airflow to one or more air separation modules.

According to another embodiment, the air flow distribution means are in the form of a plurality of valves, in particular as many valves as there are air separation modules, each arranged upstream of an air separation module.

In this way, airflow can be directed to a single, some, or all air separation modules, depending on whether the valves are used singly, partially, or all together.

Advantageously, the inert gas generator includes a check valve positioned at each outlet of each air separation module to avoid any recirculation of air when some air separation modules are not used.

The invention also relates to a method for inerting an aircraft fuel tank by means of an inert gas generator as described above. This method is noteworthy in that it consists of selectively supplying air to a single, several or all air separation modules depending on the flight phase of the aircraft.

Further advantages and features will become clearer from the following description, given as a non-limiting example of an inert gas generation system according to the invention, with reference to the accompanying drawings.

1 is a schematic diagram of an inerting system for an aircraft fuel tank; FIG. 1 is a schematic diagram of an inert gas generator, the distribution means being controlled to supply air to a single air separation module; FIG. 3 is a schematic diagram similar to that in FIG. 2, in which the distribution means are controlled to supply air to some air separation modules; FIG. 3 is a schematic diagram similar to that in FIG. 2, in which the distribution means are controlled to supply air to all air separation modules; FIG. 2 is a schematic illustration of another embodiment of an inert gas generator, wherein the air flow distribution means are in the form of a plurality of valves, each positioned upstream of an air separation module; FIG. 6 is a schematic diagram similar to that in FIG. 5 without the valve upstream of the oxygen analyzer; FIG.

Referring to FIG. 1, the present invention relates to an inert gas generator (1) comprising an air system (2) that depletes oxygen to produce a nitrogen-enriched inert gas.

The generator (1) is intended to be used in particular in an inerting system (11) for at least one aircraft fuel tank (12). For this purpose, the inert gas generator (1) is connected via an air preparation system (14), which can be subordinated to the compressor, to extract air from at least one engine and/or from the passenger compartment and/or from the aircraft. It comprises an air inlet (3) supplied with air from the outside and an inert gas outlet (4) connected to inert gas distribution means (13) in the fuel tank (12). The production system (1) also includes an oxygen enriched gas outlet (15).

The inerting system (11) makes it possible to generate an inert gas and introduce it into the aircraft fuel tank (12) for safety reasons in order to reduce the risk of explosion of the tank. The inert gas injected aims to render the fuel tank (12) inert, i.e. to reduce the level of oxygen present in said tank, in particular to bring this level to a certain threshold, preferably This makes it possible to maintain it below 12%.

With reference to Figures 2 to 5, the inert gas generator (1) comprises a plurality of air separation modules (2), ie at least two, preferably at least three, arranged in parallel on the air system.

The air separation module (2) comprises, for example, a polymeric membrane, into which pressurized air is injected to obtain both a nitrogen-rich inert gas and an oxygen-rich inert gas.

Furthermore, the inert gas generator (1) includes airflow distribution means (5) positioned upstream of the air separation module (2). According to the invention, the inert gas generator (1) comprises a control unit (6), for example an electronic board with built-in software, making it possible to control and manage the distribution means (5). There is.

More specifically, the control unit (6) controls the distribution means (5) to selectively feed a single, some or all air separation modules (2) depending on the flight phase of the aircraft. ) is programmed to control the Data relating to the flight phase of the aircraft is collected by the control unit using any suitable means and transmitted directly by the on-board computer of the aircraft, for example.

The invention thus allows air separation modules (2) to be used according to the actual requirements for the inert gas to be injected into the fuel tank (12), which vary depending on the flight phase of the aircraft. It becomes possible to adjust the number of (2).

For example, the control unit (6) is programmed to supply air to some air separation modules (2), preferably to a single air separation module (2), when the aircraft is in a cruise or climb phase. (see Figures 2 and 3) and can be programmed to supply air to a plurality, preferably all, of the air separation modules (2) when the aircraft is in the descent phase (Figure 4). reference).

From the above, it can be seen that the invention also makes it possible in some cases to reduce the total time that air separation modules (2) are used, since some modules (2) will not be used.

The invention makes it possible to optimize the size of the inerting system (11) and thus significantly reduce the airflow consumed by the inert gas generator (1) and even to optimize the size of the exchanger and filter elements become. This obviously therefore also makes it possible to reduce the cost of operating the inerting system (11) and the risk of overpressure and overtemperature in the fuel tank (12).

Based on this concept, when a single or some air separation modules (2) are supplied with air, the control unit (6) has the least accumulated operating time among the plurality of air separation modules (2). Advantageously programmed to supply air to the air separation module (2). In this way, the air separation modules (2) are selected by the control unit (6) to be used according to the accumulated operating time of these air separation modules (2), thereby reducing the wear and tear of the various air separation modules (2). are equalized, thus optimizing the lifetime of these air separation modules (2). For example, this allows an aircraft in its cruise or climb phase to switch between different air separation modules (2). This makes the inerting system longer-lasting and cheaper in operation.

According to another embodiment, when a single or some air separation modules (2) are supplied with air, the control unit (6) preferably is programmed to supply air to the air separation module (2) with the lowest performance, i.e. the lowest level of oxygen in the inert gas produced.

In order to evaluate the performance of each air separation module (2), the inert gas generator (1) is equipped with at least one oxygen analyzer (7) and at the outlet of each air separation module (2) to convert the inert gas into oxygen. It includes means for directing to the analyzer (7), in particular pipes and/or valves (8). This makes it possible to measure the performance of each air separation module (2) independently of each other.

This performance measurement can be performed in flight, for example during the descent phase, or on the ground. This makes it possible to know the performance of each of the air separation modules (2) and to alternate the use of these air separation modules (2) according to this performance.

According to a particular embodiment, shown in particular in FIGS. 2 to 4, the airflow distribution means (5) are positioned upstream of all air separation modules (2) and are arranged in a single, partial or For example in the form of a multi-channel valve (9) adapted to selectively direct the airflow to all air separation modules (2).

In another embodiment, shown in particular in Figure 5, each air separation module (2) is connected upstream to a valve (10), whereby a single It becomes possible to selectively supply air to one, some or all of the air separation modules (2). Additionally, the inert gas generator includes a check valve (16) positioned at the outlet of each air separation module.

The presence of a valve (8) downstream of the air separation module (2), whether a multi-channel valve (9) or multiple valves (10), is not essential, as shown in FIG. 6.

According to the invention, the control unit (6) thus manages the airflow distribution means (5) to selectively use and supply the air separation modules (2) depending on the flight phase of the aircraft. When a single or some air separation modules (2) have to be used, the control unit (6) provides for switching from one separation module (2) to another after a certain operating time, e.g. 1 hour. The modules (2) that have to be used are selected according to some criteria, such as performance, wear, accumulated operating time, or simply how long those separation modules (2) have been used.

Combinations of these criteria can of course be envisaged. For example, the control unit (6) can select the module (2) with the least accumulated operating time, and if two modules (2) have the same accumulated operating time, the control unit (6) The best performance of the two modules (2) can be selected. At the end of a certain operating time, the selected module (2) can then be replaced by another module (2) according to the same criteria.

The idea behind the invention is to select the number of air separation modules (2) according to the flight phase. This makes it possible to adjust the size of the inerting system (11) according to the actual requirements for inert gas in the fuel tank (12). Nevertheless, the criteria for selecting the various modules (2) can also be applied without worrying about the flight phase. For example, the selection of modules (2) can also be determined solely by wear, performance, or time intervals (time delays) of actual use, in order to equalize the wear of the various air separation modules (2).

The invention also consists of a method for inerting an aircraft fuel tank by means of an inert gas generator (1) such as the one described above. The method selectively selects a single, some or all air separation modules (2) depending on the flight phase of the aircraft and according to different criteria for selecting air separation modules (2). It is noteworthy that it consists of supplying air.

1 Inert gas generator 2 Air separation module 3 Air inlet 4 Inert gas outlet 5 Air flow distribution means 6 Control unit 7 Oxygen analyzer 8 Valve 9 Multichannel valve 10 Valve 11 Inerting system 12 Fuel tank 13 Inert gas distribution Means 14 Air preparation system 15 Oxygen enriched gas outlet 16 Check valve

Claims (8)

A generator (1) of inert gas from an air stream in an inerting system for at least one aircraft fuel tank, the generator (1) distributing said air stream to an air inlet and to a plurality of air separation modules (2). air flow distribution means (5) for depleting the air of oxygen and depleting the air of nitrogen at the outlet, said plurality of air separation modules (2) being arranged in parallel on said air system. in a generator (1) producing enriched inert gas, for selectively supplying air to a single, some or all said air separation modules (2) according to the flight phase of said aircraft; a control unit (6) of said airflow distribution means (5) programmed to
When one or some of the air separation modules (2) are supplied with air, the control unit (6) determines that among the plurality of air separation modules (2), (i) the accumulated operating time is the least; said air separation module (2) or (ii) programmed to supply air to the best performing air separation module (2);
Said generator comprises at least one oxygen analyzer (7) and said inert gas at said outlet of each air separation module (2) in order to measure the performance of each air separation module (2) independently of each other. means (5) for directing oxygen to said oxygen analyzer (7) . A generator (1) according to claim 1, wherein the control unit (6) is programmed to supply air to a single air separation module (2) when the aircraft is in a climb or cruise phase. ). A generator (1) according to claim 1 or 2, wherein the control unit (6) is programmed to supply air to all the air separation modules (2) when the aircraft is in a descent phase. ). When a single or some of said air separation modules (2) are supplied with air, said control unit (6) controls the control of said air separation modules (2) among said plurality of air separation modules (2). Generator (1) according to any one of claims 1 to 3 , wherein the generator (1) is programmed to alternate the supply of air with specified time delays. Generator (1) according to any one of the preceding claims, wherein the airflow distribution means ( 5 ) are in the form of a multi-channel valve (9). 5. The method according to claim 1 , wherein said airflow distribution means (5) are in the form of as many valves as there are air separation modules (2), each of said valves being arranged upstream of an air separation module (2). Generator (1) according to any one of the claims. Generator (1) according to any one of claims 1 to 6 , wherein the generator comprises a check valve (16) at the outlet of each air separation module (2). A generator (1) of inert gas from an air stream, comprising an air system comprising an air inlet, an inert gas outlet, and a plurality of air separation modules (2), said plurality of air separation modules. (2) inert the aircraft fuel tank by means of a generator (1) arranged in parallel on said air system to deplete the oxygen in the air and produce nitrogen-enriched inert gas at the outlet ; In the method for
selectively supplying air to a single, some or all of the air separation modules (2) depending on the flight phase of the aircraft ;
directing said inert gas at the outlet of each air separation module (2) to at least one oxygen analyzer (7);
measuring the performance of each air separation module (2) independently of each other by said at least one oxygen analyzer (7);
A method consisting of.

Images